The AMR file type is primarily associated with ‘Adaptive Multi-Rate ACELP Codec’. Speech encoding format used in GSM telephony. The AMR ACELP coder will lower the compression rate as cellular interference increases, thus enabling more error correction to be applied. It also is used to harmonize the codec standards amongst different cellular systems. (ACELP = Algebraic Code Excited Linear Prediction) Detailed information for file extension AMR: Primary association: Adaptive Multi-Rate ACELP Codec File classification: Audio Mime type: audio/AMR Identifying characters Hex: 23 21 41 4D 52 0A 34 , ASCII: #!AMR 4 Program ID: QuickTime.AMR , RealPlayer.AMR.10 , Related links: Player, Background Paper, Quicktime, Real Player, Mobile AMR Converter